net: sched: set xt_tgchk_param par.nft_compat as 0 in ipt_init_target

Commit 55917a2 ("netfilter: x_tables: add context to know if
extension runs from nft_compat") introduced a member nft_compat to
xt_tgchk_param structure.

But it didn't set it's value for ipt_init_target. With unexpected
value in par.nft_compat, it may return unexpected result in some
target's checkentry.

This patch is to set all it's fields as 0 and only initialize the
non-zero fields in ipt_init_target.

v1->v2:
  As Wang Cong's suggestion, fix it by setting all it's fields as
  0 and only initializing the non-zero fields.

Fixes: 55917a2 ("netfilter: x_tables: add context to know if extension runs from nft_compat")
Suggested-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/act_ipt.c

@@ -49,9 +49,9 @@ static int ipt_init_target(struct net *net, struct xt_entry_target *t,
 		return PTR_ERR(target);
 
 	t->u.kernel.target = target;
+	memset(&par, 0, sizeof(par));
 	par.net       = net;
 	par.table     = table;
-	par.entryinfo = NULL;
 	par.target    = target;
 	par.targinfo  = t->data;
 	par.hook_mask = hook;